Cxc12 expression and secretion are increased in OB/P Cx43-deficient BM. (A-C) Western blot of whole BM lysates analyzed for Cxcl12 expression basally (A) and after G-CSF administration (C). (B-D) Extracellular BM Cxcl12 levels determined by ELISA in WT and OB/P Cx43-deficient BM from steady-state and lethally irradiated mice (16 hours after irradiation; B) and in nonmyeloablated mice after G-CSF administration (D). Empty bars represent control (WT) values and solid bars represent OB/P Cx43-deficient values. Data are shown as mean ± SEM of 3 independent experiments with a minimum of 5 mice per group (*P < .05; **P < .01).